The first structure that was demolished was a network of eight low-rise buildings with an estimated 600 residents.

People were warned a week ago to vacate, but many were seen taking their possessions out on Friday morning.

Another 90 houses will be pulled down next. Other areas affected include Roysambu, Hazina, Zimmerman, Kahawa West, Umoja and Dagoretti.

Image captionPeople raced against time to take their belongings out of their homesImage captionResidents had been told to vacate a week agoImage captionBuildings lined up for demolition are marked with a red cross

The six-storey building collapsed on 29 April, at the height of Kenya’s rainy season.

A local MP said it was built less than 5m (15 feet) from a river, when it should have been at least 30m away.

The National Construction Authority said it had marked the building as unfit for habitation, but that the local government had failed to follow up.

Image copyrightEPAImage captionThe rescue operation began shortly after the building collapsed on Friday

The two owners of the building were taken into custody but released on $5,000 (£3,450) bail Wednesday, pending formal charges.

Many of Nairobi’s four million people live in low-income areas or slums. Housing is in high demand, and unscrupulous developers often bypass regulations.

Pulled out alive

As rescue operations continue, four people were pulled out alive on Thursday.

Crowds cheered as 24-year-old woman was rescued, in scenes broadcast live on Kenyan TV.

Rescuers had smashed through slabs of concrete to reach Elizabeth Night Odhiambo, who was eight months pregnant.

Image captionElizabeth Night Odhiambo was given an intravenous drip and oxygen while rescuers tried to dig her outImage copyright: Ms Odhiambo was rushed to hospital and survived, but she lost her baby

Soldiers, firefighters and volunteers have been searching for survivors since the 29 April collapse of the building.

Trained dogs had been brought in, along with special equipment to detect breathing and movement, military spokesman David Obonyo told AP news agency.